如何在shell腳本中使用goto語句

Question

我是shell腳本的初學者。我不知道如何使用goto語句。我正在使用下面的代碼。

start: 
echo "Main Menu" 
echo "1 for Copy" 
echo "2 for exit" 
read NUM 
case $NUM in 
"1") 
echo "CopyNUM" 
goto start:; 
"2")   
echo "Haiiii"; 
goto start: 
*) 
echo "ssss"; 
esac 

Answer 1

正如其他人所指出的那樣，有一個在bash沒有goto（或其他POSIX樣彈） - 其它更爲靈活的流量控制結構取而代之。
在man bash中查找標題Compound Commands。

對您而言，select命令是正確的選擇。 由於如何使用它可能不是很明顯，這裏的東西讓你開始：

#!/usr/bin/env bash 

echo "Main Menu" 

# Define the choices to present to the user, which will be 
# presented line by line, prefixed by a sequential number 
# (E.g., '1) copy', ...) 
choices=('copy' 'exit') 

# Present the choices. 
# The user chooses by entering the *number* before the desired choice. 
select choice in "${choices[@]}"; do 

    # If an invalid number was chosen, $choice will be empty. 
    # Report an error and prompt again. 
    [[ -n $choice ]] || { echo "Invalid choice." >&2; continue; } 

    # Examine the choice. 
    # Note that it is the choice string itself, not its number 
    # that is reported in $choice. 
    case $choice in 
    copy) 
     echo "Copying..." 
     # Set flag here, or call function, ... 
     ;; 
    exit) 
     echo "Exiting. " 
     exit 0 
    esac 

    # Getting here means that a valid choice was made, 
    # so break out of the select statement and continue below, 
    # if desired. 
    # Note that without an explicit break (or exit) statement, 
    # bash will continue to prompt. 
    break 

done 

Answer 2

下面是一個使用select循環來實現自己的目標的一個小例子。您可以使用while循環使用自定義菜單，如果你想自定義格式，但基本的菜單是什麼select設計要做到：

#!/bin/bash 

## array of menu entries 
entries=("for Copy" 
      "for exit") 

## set prompt for select menu 
PS3='Selection: ' 

while [ "$menu" != 1 ]; do    ## outer loop redraws menu each time 
    printf "\nMain Menu:\n\n"    ## heading for menu 
    select choice in "${entries[@]}"; do ## select displays choices in array 
     case "$choice" in     ## case responds to choice 
      "for Copy") 
       echo "CopyNUM" 
       break      ## break returns control to outer loop 
       ;; 
      "for exit")   
       echo "Haiiii, exiting" 
       menu=1     ## variable setting exit condition 
       break 
       ;; 
      *) 
       echo "ssss" 
       break 
       ;; 
     esac 
    done 
done 

exit 0 

使用/輸出

$ bash select_menu.sh 

Main Menu: 

1) for Copy 
2) for exit 
Selection: 1 
CopyNUM 

Main Menu: 

1) for Copy 
2) for exit 
Selection: 3 
ssss 

Main Menu: 

1) for Copy 
2) for exit 
Selection: 2 
Haiiii, exiting